Previously proposed is a walking assistance device that includes a power generator such as an electric motor to apply a working assistance force to a lower limb of a user for the purposes of assisting the walking movement of the user, and/or rehabilitating the walking impairment of the user by helping the user to regain the motor coordination that is required for the user to walk.
Such a walking assistance device typically includes a pelvic frame consisting of a C-shaped main frame configured to be worn on a pelvic part of the user and extending from a lower back part of the user to either side of the pelvic part of the user and an abdominal belt for securing the main frame to the pelvic part of the user, a pair of power generators mounted on either lateral end of the pelvic frame (at parts corresponding to the hip joints of the user) and a pair of femoral support members for transmitting the power generated by the power generators to the corresponding femoral parts of the user. See patent document 1 (Japanese patent laid-open publication JP2009-95645A).
A walking assistance device of this kind requires an electronic control unit and a battery for executing the required control action and providing the electric power to the power generator. It is most convenient if such electronic/electric units can be mounted on the pelvic frame. However, because the pelvic support assembly is worn closely on the body of the user, and is limited in space, there is some difficulty in placing the electronic/electric units on or in the pelvic frame.
Also, the pelvic frame is configured to support the load (weight and reaction force) of the walking assistance device, and is given with an adequate mechanical strength, but inevitably undergoes some deformation during use. If the deformation of the main frame is transmitted to the electronic/electric units, the durability and reliability of the electronic/electric units may be impaired. This problem can be overcome by increasing the stiffness of the main frame, but it adds to the weight and cost of the main frame.
It is also important that the electronic/electric units are placed in such a part of the walking assistance device that can be readily accessed in view of the need to service the electronic/electric units and replace a component thereof from time to time.
The electronic/electric units often generate heat in operation, and there may be a need to insulate the user from the heat.
It is known to provided a back support member on a middle part of the main frame facing a lower back part of the user for the purpose of evenly distributing the load (weight and reaction force) of the walking assistance device uniformly over the body of the user and maximize the comfort of the user. See patent document 2 (Japanese patent laid-open publication JP2005-000634A). The inventors have realized that the back support member can be used not only for supporting a lower back part of the user but also as a part of the enclosure for receiving electronic/electric units and prevent the transmission of heat from the electronic/electric units of the user.